When fuel is burned to heat water in boiler or air in a heat exchanger, a fuel such as natural gas, propane, kerosene, heating oil or coal is combined with oxygen to release heat. Combustion is complete when a hydrocarbon fuel is converted into carbon dioxide and water. Incomplete and inefficient combustion may produce unused heat and byproducts of combustion including carbon monoxide, carbon dioxide, and oxides of nitrogen and sulfur. The presence of carbon monoxide not only indicates inefficient combustion but is also a safety hazard. The temperature of flue gas is inversely proportional to efficiency. An inefficient burner literally sends energy up the chimney. For reasons of safety, efficiency and regulatory compliance, it is important to monitor the temperature of the combined combustion gases in a flue as well as the types of gases produced and the concentration of each gas as a percent of the total of all combustion gases. Gas analyzers measure the efficiency of flue gas and identify the component gases in flue gas and the concentration of each component.
Over a period of operation, burners for boilers or hot air heating systems may become less efficient, unsafe or non-compliant with environmental regulations. In order to adjust the burner to maximize efficiency, safety and compliance, a technician uses a gas analyzer to measure the temperature of the flue gas and identify the types of gases and concentration of each gas in the flue gas. Using that information, a technician may adjust the relative and total amounts of fuel and air used by the burner to combust the fuel. While 100% efficiency is not possible, it is realistic to adjust burners to achieve close to 95% efficiency. High rise office buildings and high rise residences may have three or more boilers that consume thousands of gallons of heating fuel or thousands of cubic feet of natural gas. Even a small improvement of 2-3% in efficiency could save hundreds of thousands of dollars.
Conventional flue gas analyzers are often hand held devices with a sensor for temperature and multiple sensors of different types of gases and concentrations of gases. Combustion gas is sampled by inserting a probe into an access aperture of a flue. The probe is a long tube with a handle grip. The tube is in fluid communication with an outlet at the bottom of the handle. A flexible hose that is several feet long connects the outlet of the handle to a hand held gas analyzer. The analyzer has a pump with an inlet connected to the hose. The pump applies suction to the hose and draws a sample of flue gas into the analyzer. A filter is located between the outlet of the pump and the sensors. The gas sample passes through the filter which removes soot and other particulates that could damage sensitive temperature and gas sensors in the gas analyzer.
A technician inserts the probe into a flue and turns on the pump to acquire a sample of the flue gas. The gas analyzer displays the flue gas temperature, the types of gases in the sample, and the concentration for each component gas. With the probe in the flue and display in sight, the technician makes one or more adjustments to the burner, including changing the amount of air or fuel of both to maximize efficiency, minimize safety hazards, and comply with government regulations.
Conventional gas analyzers have a number of drawbacks that make it difficult for the technician to properly adjust the burner. Sometimes the probe slips out of the flue aperture and the process must be restarted. The pump is relatively small and slowly draws the gas sample which may cool before reaching the temperature sensor in the gas analyzer. Even if the hose is relatively short, some cooling is inevitable and the temperature reading is inaccurate. There may be insufficient space in the boiler room to simultaneously display the results and permit the technician to adjust the burner. For example, a hose short enough to minimize cooling may not be long enough to reach a location where the technician may see the display while making air and fuel adjustments. The foregoing are representative of problems addressed by the embodiments described in this patent.